Channelizing a wideband waveform for transmission on a spectral band comprising unavailable channel segments

ABSTRACT

Methods, systems, and devices for channelizing a wideband waveform for transmission on a spectral band comprising unavailable channel segments are described. Generally, the described techniques provide for transmitting and receiving wideband waveforms when channels of a system bandwidth are unavailable for transmission. A transmitter may separate a first wideband signal into segments, with each segment a bandwidth corresponding to a channel of the system bandwidth, and may map the segments to the available channels. The transmitter may combine the mapped segments into a second wideband waveform and transmit the second wideband waveform using the available channels. A receiver may receive a first wideband signal waveform and may separate the first wideband signal waveform into segments, de-map the segments and combine the de-mapped segments into a second wideband waveform for demodulation. The techniques may be used to transmit and receive wideband waveforms over tactical data links.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/598,201 filed Oct. 10, 2019, the disclosure of which is herebyincorporated in its entirety for all purposes.

BACKGROUND

The following relates generally to wideband communications, and morespecifically to channelizing a wideband waveform for transmission on aspectral band comprising unavailable channel segments.

Wired and wireless communications systems are widely deployed to providevarious types of communication content such as voice, video, packetdata, messaging, broadcast, and so on. Some communications systems maybe used in the context of secure communications, such as tacticalcommunications. In addition, some communication systems may experiencefrequency-dependent interference. Such communications systems may besubject to various constraints and challenges.

SUMMARY

The described techniques relate to improved methods, systems, devices,and apparatuses that support channelizing a wideband waveform fortransmission on a spectral band comprising unavailable channel segments.Generally, the described techniques provide for transmitting andreceiving wideband waveforms when channels of a system bandwidth areunavailable for transmission. The described techniques may includetechniques for transmitting a wideband waveform via a spectral bandcomprising unavailable channel segments. The techniques may includeidentifying a subset of a plurality of channels of a system bandwidthavailable for a transmission in a time period, generating a firstwideband waveform having a bandwidth determined according to a number ofchannels in the subset of the plurality of channels, separating thefirst wideband waveform into a plurality of segments, mapping theplurality of segments to the subset of the plurality of channels of thesystem bandwidth, combining the mapped plurality of segments to generatea second wideband waveform, and transmitting the second widebandwaveform in the time period.

The described techniques may include techniques for receiving a widebandwaveform via a spectral band comprising unavailable channel segments.The techniques may include identifying a subset of a plurality ofchannels of a system bandwidth available for a transmission in a timeperiod, receiving a first wideband waveform in the time period,separating the first wideband waveform into a plurality of waveformsegments corresponding to the subset of the plurality of channels,de-mapping the plurality of waveform segments based at least in part onthe subset of the plurality of channels, combining the de-mappedplurality of waveform segments to obtain a second wideband waveform, anddemodulating the second wideband waveform to obtain a stream of bits.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a wireless communication system thatsupports channelizing a wideband waveform for transmission on a spectralband comprising unavailable channel segments in accordance with aspectsof the present disclosure.

FIG. 2 illustrates an example of a transmitter that supportschannelizing a wideband waveform for transmission on a spectral bandcomprising unavailable channel segments in accordance with aspects ofthe present disclosure.

FIG. 3 illustrates an example of a transmitter that supportschannelizing a wideband waveform for transmission on a spectral bandcomprising unavailable channel segments in accordance with aspects ofthe present disclosure.

FIG. 4 illustrates an example of a spectrum plot that supportschannelizing a wideband waveform for transmission on a spectral bandcomprising unavailable channel segments in accordance with aspects ofthe present disclosure.

FIGS. 5A and 5B illustrate an example of a polyphase analysis bank andan example of a polyphase synthesis bank that support channelizing awideband waveform for transmission on a spectral band comprisingunavailable channel segments in accordance with aspects of the presentdisclosure.

FIG. 6 illustrates an example of a receiver that supports channelizing awideband waveform for transmission on a spectral band comprisingunavailable channel segments in accordance with aspects of the presentdisclosure.

FIG. 7 illustrates an example of a device that supports channelizing awideband waveform for transmission on a spectral band comprisingunavailable channel segments in accordance with aspects of the presentdisclosure.

FIGS. 8 and 9 show flowcharts illustrating methods that supportchannelizing a wideband waveform for transmission on a spectral bandcomprising unavailable channel segments in accordance with aspects ofthe present disclosure.

DETAILED DESCRIPTION

Wireless communications systems used for secure communications, such asfor tactical communications between military entities, may be subject tovarious constraints and challenges. For example, such communications maybe expected to provide a high level of robustness to external tampering,a high level of reliability, etc. The Link 16 communication protocol isan example of a tactical data link that may provide various advantagesfor tactical communications, such as providing a relatively high levelof security for transmissions. Link 16 was originally developed fortactical airborne air-to-air communications and supports voicecommunications and limited data communications. The spectrum used byLink 16 has been highly regulated, and the protocol was designed tosupport sparse waveforms that use relatively little spectrum. Tacticaldata links such as Link 16 may operate as primary user (e.g.,prioritized over other users), a secondary user (e.g., a lower priorityuser than at least one other user), or as a tertiary user (e.g., as auser that obtains permission to use spectrum for transmission).

In recent years the use of Link 16 has expanded and the risks of jammingand other undesirable interference have increased. Because tactical datalinks such as Link 16 operate on older physical layers and underrelatively tight regulation, however, increasing the capacity (e.g.,throughput), spectrum efficiency, and security—particularly whilemaintaining backward compatibility—may be challenging.

Traditional data links may use single-channel transmission. In thiscase, if a particular transmission channel is jammed or otherwiseunavailable for transmission, the transmitter may select a differentchannel if available. However, in single-channel transmissions, thetransmission energy may be concentrated within the channel and may bemore easily detectible or jammable.

As described herein, a transmitter may provide better anti-jammingperformance, better throughput, and/or better spectrum efficiency bygenerating a wideband waveform representing the data to be transmittedand mapping the wideband waveform to multiple available channels. Inthis case, the information may be spread across multiple channels toreduce detectability of the signal, improve transmission quality andthroughput, and mitigate the effect of channel jamming.

For example, in some cases, a transmitter used in a system fortransmitting wideband waveforms over a tactical data link may receive astream of bits for transmission (e.g., from a processor in the system),and may generate a wideband waveform based on the stream of bits. Insome cases, the system may be configured to transmit wideband waveformsusing a system bandwidth that may include or may be partitioned intomultiple channels, where each channel may have a predetermined (e.g.,the same) channel bandwidth. In some cases, not all of the channels ofthe system bandwidth may be available for transmission, such as if oneor more of the channels are used for other communications or jammed by amalicious entity.

The transmitter may identify a subset of the channels that are availablefor transmission (e.g., channels that are unused or unjammed, asdetermined based on the signal power of the channels). The transmittermay separate the first wideband signal into segments, with each segmenthaving the channel bandwidth, and may map the segments to the availablechannels. The transmitter may combine the mapped segments into a secondwideband waveform and transmit the second wideband waveform using theavailable channels. In this manner, the transmitter may use all of theavailable channels together and spread the energy across them—that is,the energy of each bit of data may be spread across multiple channels.In this case, jamming a channel may have limited effect on the qualityof the transmission, since it may only affect a small part of the energyof transmission associated with the data.

Although the discussion herein focuses on wireless communications using,for example, tactical data links, such techniques may also be used forother wireless or wireline communications. For example, various wirelessor wireline communication environments may experience spectral holesthat are not available for transmission (e.g., due to impedancemismatching or due to interference). One such example may be digitalsubscriber line (DSL) communications, however other examples will beapparent to one of skill in the art. Moreover, such techniques may beapplied to other types of signals that are transmitted and received,such as radar signals and sonar signals, and may be used in applicationssuch as in hearing aids.

Aspects of the disclosure are initially described in the context of awireless communications system. Aspects of the disclosure are furtherillustrated by and described with reference to apparatus diagrams,system diagrams, and flowcharts that relate to channelizing a widebandwaveform for transmission on a spectral band comprising unavailablechannel segments.

FIG. 1 illustrates an example of a communication system 100 that mayemploy channelizing a wideband waveform for transmission on a spectralband comprising unavailable channel segments, according to variousaspects of the disclosure. Communication system 100 includes devices 105that may be capable of wireless communication using a tactical data link110. Devices 105 may be a handheld device carried by a user, or may belocated in a vehicle such as aircraft, tank, ship, or other type ofvehicle. Tactical data link 110 may support secure communicationsbetween devices 105 and may include frequency hopping capabilities.Frequency hopping may refer to rapidly switching a carrier amongdifferent frequency channels using a sequence (e.g., a pseudorandomsequence) known to both transmitter and receiver. For example, tacticaldata link 110 may support frequency hopping at 13 microsecond intervalsor at other relatively short intervals.

Tactical data link 110 may enable devices 105 to communicate on a systembandwidth that includes multiple channels having predeterminedbandwidths (e.g., each channel having the same bandwidth). In somecases, not all of the channels may be available for transmission. Forexample, in some cases tactical data link 110 may transmit on a datalink network platform having a spectral band (e.g., a system bandwidth)comprising N bandwidth segments (e.g., channels) only M of which may beavailable at any given time. In some cases, a tactical data link 110 mayhave a spectral band of 240 MHz (e.g., a band that ranges from 967.5 to1207.5 MHz), where N is 80 channels each comprising 3 MHz and M is 51 orless.

In some cases, tactical data link 110 may be a time division multipleaccess (TDMA) platform in which each user is assigned one or more timeslices in which to transmit. A transmitting user may transmit a messageas a sequence of encoded pulses, which are frequency-hopped in a uniquehopping pattern among the channels within a time slice. In some cases,each pulse may have a bandwidth equal to a channel bandwidth, and may bemapped to one of the channels according to the hopping pattern. In somecases, the hopping pattern is known to the receiving user. Use ofhopping patterns may allow multiple users to transmit in the same timeslice. In some cases, each user transmitting in the same time slice butusing a different hopping pattern may be referred to as transmitting ona different “net.” In some cases, transmissions may include parallelpulses on each available channel. However, if one or more channels onwhich the pulses are mapped is jammed or has substantial interference,the link performance may degrade substantially.

According to various aspects of the disclosure, a transmitter mayenhance performance over a segmented spectral band by generating awideband waveform representing the data to be transmitted and mappingthe wideband waveform to multiple available channels. Channelizing thewideband waveform may provide better anti-jamming performance, betterthroughput, and/or better spectrum efficiency. For example, theinformation may be spread across multiple channels to reducedetectability of the signal, improve transmission quality andthroughput, and mitigate the effect of channel jamming.

A transmitter used in a system for transmitting wideband waveforms overa tactical data link may receive a stream of bits for transmission(e.g., from a processor in the system), and may generate a widebandwaveform based on the stream of bits. In some cases, the system may beconfigured to transmit wideband waveforms using a system bandwidth thatmay include or may be partitioned into multiple channels, where eachchannel may have a predetermined (e.g., the same) channel bandwidth. Insome cases, not all of the channels of the system bandwidth may beavailable for transmission, such as if one or more of the channels areused for other communications or jammed by a malicious entity.

The transmitter may identify a subset of the channels that are availablefor transmission (e.g., channels that are unused or unjammed, asdetermined based on the signal power of the channels). The transmittermay separate the first wideband signal into segments, with each segmenthaving the channel bandwidth, and may map the segments to the availablechannels. The transmitter may combine the mapped segments into a secondwideband waveform and transmit the second wideband waveform using theavailable channels. In this manner, the transmitter may use all of theavailable channels together and spread the energy across them—that is,the energy of each bit of data may be spread across multiple channels.In this case, jamming a channel may have limited effect on the qualityof the transmission, since it may only affect a small part of the energyof transmission associated with the data.

FIG. 1 illustrates a system bandwidth 130 including 15 channels withthree devices 105 transmitting over three different nets 115 of tacticaldata link 110 during a time slice 120. For example, a first device 105-amay transmit over net A 115-a, a second device 105-b may transmit overnet B 115-b, and a third device 105-c may transmit over net C 115-c.Each of the devices may concurrently receive or listen to one or morenets 115. For example, device 105-a may transmit over net 115-a whilereceiving net B 115-b and net C 115-c. Alternatively, some devices 105may only transmit or receive during a given time slice 120. First device105-a may transmit using three channels 135 during each pulse period 125in time slice 120, where the channels 135 used by first device 105-a foreach pulse period 125 of time slice 120 may be determined by the hoppingpattern associated with net A 115-a. For each time slice 120, device105-a may determine an available subset of the system bandwidth 130. Forexample, device 105-a may determine a number of channels that areconfigured for net A 115-a for time slice 120. Additionally oralternatively, device 105-a may determine a subset of channels 135available for the time slice 120, which may be based on a configurationfor the system bandwidth (e.g., for one or more time slices 120). Inaddition, one or more channels 135 may be unavailable due tointerference (e.g., jamming) For example, device 115-a may be configuredto use three channels 135 per pulse period 125 of time slice 120, andmay determine that 13 of the 15 channels of the system bandwidth areavailable for time slice 120. In addition, device 105-a may determinethat one or more channels 135 have an interference level that meets orexceeds a threshold. In one example, device 105-a may determine thatchannels 7 and 8 have excessive interference during time slice 120.Device 105-a may be mapped to different subsets (e.g., provisionalsubsets) of three channels 135 per pulse period 125. For each pulseperiod 125 where net A 115-a is mapped to one or more of channels 7 and8, device 105-a may allocate transmission power to the other channelsassociated with the pulse period 125. For example, for pulse periods 8,6, and 4 of time slice 120, device 105-a may allocate its transmissionpower between the other two channels 135 (e.g., allocating zero power tochannels 7 and 8), while in the other pulse periods device 105-a mayallocate its transmission power between three channels 135. In somecases, devices 105 may make a determination of available channels on apulse period 125 basis. For example, device 105-a may receive oridentify an indication of a provisional subset of channels for a givenpulse period 125, and may make a determination of the available channelsof the provisional subset of channels (e.g., based on interference).

Although illustrated as having 15 total channels, tactical data link 110may have any number of channels, and an arbitrary number up to andincluding all of the total number of channels may be available for eachtime slice 120. Each net 115 may also be associated with varying numbersof channels for each pulse period, up to and including the number ofavailable channels. Although nets A, B, and C are illustrated in FIG. 1as having non-overlapping hopping patterns, hopping patterns for nets115 may overlap during one or more pulse periods 125 of a time slice120, in some cases. Although FIG. 1 depicts three pulses (e.g., on threechannels 135) on each net 115 per pulse period 125, in some cases,tactical data link 110 may support a different number of pulses on eachnet 115, such as one pulse per net 115 per pulse period 125.

FIG. 2 illustrates an example of a transmitter 200 that supportschannelizing a wideband waveform for transmission on a spectral bandcomprising unavailable channel segments in accordance with aspects ofthe present disclosure. In some examples, transmitter 200 may beincluded in a wireless communication system, such as wirelesscommunication system 100.

Transmitter 200 may be configured to wirelessly transmit widebandwaveforms over a tactical data link using one or more antennas 275 and atransmitter backend 272. In some cases, a wideband waveform may be awaveform that spans a relatively wide band of frequencies, and may be aspread spectrum waveform Transmitter 200 may be configured to transmitwideband waveforms using a system bandwidth, which may be a band offrequencies over which transmitter 200 may transmit signals. In somecases, a system bandwidth may be partitioned into channels, with eachchannel having a respective bandwidth (e.g., the same channelbandwidth). In some cases, one or more channels of the system bandwidthmay be unavailable for transmissions if, for example, the channels areexcluded from a subset of configured available channels or are jammed byinterfering signals (e.g., other transmissions or intentional jamming)In some cases, transmitter 200 may identify a channel set 215 (e.g., aset of channels selected for transmission) and may transmit widebandwaveforms using the channel set 215, as described in more detail herein.In some examples, the channel set 215 may correspond to all of theavailable channels, while in some cases channel set 215 may be a subsetof the available channels (e.g., a configured number of channels). Insome cases channel set 215 may be determined by excluding channels fromthe available channels or configured channels that have a level ofsignal power (e.g., interference) that satisfies (e.g., meets orexceeds) a threshold.

In operation, transmitter 200 may receive a stream of bits 205, such asdata bits for transmission. In some cases, the stream of bits 205 may bereceived for transmission in a time period (e.g., a pulse period). Insome cases, transmitter 200 may receive the stream of bits 205 from aprocessor or other device that is coupled with transmitter 200.Transmitter 200 may include a modulator 210 for modulating the stream ofbits 205 to generate a first wideband waveform 220. In some cases,modulator 210 may receive an indication of channel set 215, and maymodulate the stream of bits 205 based on the number of channels inchannel set 215. For example, a device that includes transmitter 200 mayidentify a total number of channels of a system bandwidth and a set ofavailable channels for a time slice or pulse period (e.g., configuredfor the time slice or pulse period, or having a signal power level thatdoes not satisfy a threshold). The device may determine channel set 215from the set of available channels (e.g., a subset or all of the set ofavailable channels).

In some cases, channel set 215 may exclude channels that have signalpower satisfying the threshold (e.g., due to excessive use orintentional jamming) In some cases, the channel set 215 may benon-contiguous; that is, at least two channels in the channel set 215may be separated by one or more channels that are excluded from thechannel set 215.

In some cases, the modulator 210 may modulate the stream of bits 205 togenerate a first wideband waveform 220 having a bandwidth that is equalto an aggregate bandwidth of the channels in the channel set 215. Forexample, where the bandwidth of the channels are the same, the bandwidthof first wideband waveform 220 may be determined by the number ofchannels in channel set 215 multiplied by the channel bandwidth. In oneexample, transmitter 200 may be configured to transmit via M segments,each segment having a bandwidth of B MHz. Thus, the bandwidth of thefirst wideband waveform may be equal to M·B MHz. Where the bandwidths ofthe channels are not the same, the bandwidth of first wideband waveform220 may be determined by summing the bandwidths of the channels inchannel set 215.

In some cases, modulator 210 may be a variable modulator that may selecta modulation scheme (e.g., from a set of modulation schemes) formodulating the stream of bits 205 based on various factors. For example,modulator 210 may select a modulation scheme based on the channel set215 and/or on a desired coding rate, block error rate (BLER), orthroughput. In some cases, the modulation scheme may specify, forexample, a modulation type (e.g. BPSK, QPSK, 16 QAM, etc.), a type ofcode (e.g., convolutional code, LDPC code), and a code rate (e.g., arate 1/3 code, a rate 5/8 code).

Transmitter 200 includes analyzer 230. Analyzer 230 includes segmenter235 for separating the first wideband waveform 220 into multiplesegments 225. Segments 225 may have respective bandwidths correspondingto channel bandwidths of the channel set 215 (e.g., the same bandwidth).In some cases, segmenter 235 may separate the first wideband waveform220 into segments 225 by applying multiple filters (such as bandpassfilters (BPFs)) to the first wideband waveform 220. In some cases,segmenter 235 may include a series of filters to separate first widebandwaveform 220 into segments 225, and may be implemented using a polyphasefilter. Each segment 225 may have an effective symbol timing that isless (e.g., substantially less) than the symbol timing (e.g., pulseperiod). That is, each segment 225 may carry information associated withmultiple symbols in each symbol period or pulse period.

In some cases, analyzer 230 includes downconverter 240 to downconvertthe segments 225 to baseband segments 245 For example, segments 225 mayeach be associated with different frequency ranges and downconverter 240may downconvert each segment to a baseband frequency range.

Transmitter 200 includes mapper 250 for mapping the segments (e.g.,baseband segments 245) to the corresponding frequency ranges of channelset 215. In some cases, the remaining channels (e.g., channels of thesystem bandwidth that are not in channel set 215) may be set to nullvalues. For example, mapper 250 may output a null segment or null signalfor channels of the system bandwidth that are not in channel set 215. Anull segment may be a signal having no signal energy within the basebandfrequency range.

Mapper 250 may map segments 225 to channel set 215 in an order of thesegments 225. Alternatively, mapper 250 may scramble an order of thesegments 225 among channel set 215 such that the segments 225 are mappedto channel set 215 out of order relative to the order of the segments,as depicted in FIG. 2 . For example, adjacent segments may not be mappedto adjacent channels of channel set 215. Where a scrambled order isused, mapping of non-adjacent segments to adjacent channels of channelset 215 may cause aliasing of signal energy from adjacent segments atthe receiver. Thus, groups of segments may be mapped to contiguousblocks of channels of channel set 215. That is, groups of contiguousblocks of channel set 215 may be identified, and sub-groups ofcontiguous segments 225 may be mapped to each of the groups ofcontiguous blocks. Mapper 250 may output mapped segments 251 tosynthesizer 255.

In some examples, mapper 250 may perform additional processing. Forexample, mapper 250 may perform multipath equalization of segments 225or mapped segments 251 before outputting mapped segments 251.

Transmitter 200 includes synthesizer 255 for generating a secondwideband waveform 270. Synthesizer 255 includes upconverter 260 forupconverting the mapped segments to higher frequencies. Synthesizer 255includes combiner 265 for combining the upconverted segments and holesin the spectrum (corresponding to the null values) into a secondwideband waveform 270 having a bandwidth corresponding to the channelset 215 (e.g., extending from a first channel of channel set 215 havinga lowest frequency to a second channel of channel set 215 having ahighest frequency). Second wideband waveform 270 may have a bandwidththat is wider than first wideband waveform 220. Second wideband waveformmay include null frequency ranges (e.g., corresponding to frequencychannels of the system bandwidth that are not in channel set 215).

In some cases, by generating the second wideband waveform 270 asdescribed herein, the energy of each bit of the stream of bits 205 maybe spread over the channels in second wideband waveform 270 and maytherefore be less susceptible to data loss due to jamming of a singlechannel.

In some cases, transmitter 200 may include a transmitter backend 272that includes hardware or software to implement additional processing onsecond wideband waveform 270 before transmission using one or moreantennas 275. For example, the second wideband waveform 270 may beupconverted to passband before transmission.

In some cases, the transmitted signal (e.g., the transmitted secondwideband waveform) will carry the information in the first widebandwaveform that is output by the modulator, but there may be substantialenergy only in the channels of channel set 215. In this case, thetransmitted signal may not interfere with signals transmitted (e.g., byother transmitters) in the other channels of the system bandwidth.

In one example, a system bandwidth of 45 MHz may be configured with 3MHz channels (e.g., 15 channels). Transmitter 200 may identify a channelset 215 for a first time period (e.g., a first pulse period) thatincludes channels 1-5, 8-10, 13, and 15 (e.g., including 10 of the 15channels). Modulator 210 may generate a first wideband waveform 220having a bandwidth of 30 MHz and analyzer 230 may segment anddownconvert each segment to generate 10 baseband segments 245, eachrepresenting a portion (e.g., 3 MHz) of the 30 MHz bandwidth, and eachhaving a baseband frequency range of 0-3 MHz. Mapper 250 may map thebaseband segments 245 to the channel set 215, and may map null waveformsto channels of the system bandwidth not in channel set 215. Mapper 250may map the baseband segments 245 to channel set 215 in order, or mapper250 may map the baseband segments 245 to channel set 215 in a scrambledorder. For example, mapper 250 may map baseband segment 1 to channel 13,baseband segments 2-4 to channels 8-10, baseband segments 5-9 tochannels 1-5, and baseband segment 10 to channel 15. Synthesizer 255 mayupconvert the mapped segments 251 to corresponding frequencies ofchannel set 215 and combine the upconverted segments to obtain a secondwideband waveform 270. In this example, second wideband waveform 270 mayhave a bandwidth of 45 MHz, with substantially no signal energy inchannels 6, 7, 11, 12, and 14. In instances where channel set 215 doesnot include channel 1 or channel 15, second wideband waveform 270 mayhave a bandwidth of less than the system bandwidth of 45 MHz (e.g.,where one or more segments are not mapped to the upper or lower channelsof the system bandwidth).

Transmitter 200 may identify a new channel set 215 for a second timeperiod (e.g., a second pulse period), and may perform the segmenting,downconverting, mapping, upconverting, and combining to generate asecond wideband waveform 270 for the second time period. For example,transmitter 200 may identify a new channel set 215 every pulse period,or every fourth, eighth, or twelfth pulse period, or every time slice,or at some other time period. New channel set 215 may be different thanthe channel set 215 for the first pulse period and may or may not haveany channels in common with the previous channel set 215. For example,new channel set 215 may have the same or a different number of channels.It should be understood that this example is provided for the sake ofclarity, and other system bandwidths and channel bandwidths arecontemplated without deviating from the scope of the application. Forexample, the system bandwidth may be 240 MHz, and the system may have 80channels where each channel has a 3 MHz channel bandwidth. Channel set215 may have up to 51 channels in each pulse period and thus firstwideband waveform 220 may have a bandwidth of up to 153 MHz while secondwideband waveform 270 may have a bandwidth of up to 240 MHz (e.g., thesystem bandwidth).

FIG. 3 illustrates an example of a portion of a transmitter 300 thatsupports channelizing a wideband waveform for transmission on a spectralband comprising unavailable channel segments in accordance with aspectsof the present disclosure. In some examples, transmitter 300 mayimplement aspects of wireless communication system 100 or transmitter200.

Transmitter 300 includes analyzer 230-a, mapper 250-a, and synthesizer255-a, which may be examples of analyzer 230, mapper 250, andsynthesizer 255 of FIG. 2 , respectively. A first wideband waveform220-a may be input to analyzer 230-a. Analyzer 230-a includes multiplebandpass filters 332, downconverters (DCs) 334, and decimators 336.Band-pass filters 332 may each be associated with a frequency range ofthe first wideband waveform 220-a. For example, the first widebandwaveform 220-a may have a bandwidth corresponding to an aggregatebandwidth of a number of segments in a channel set 215-a configured fortransmission within a pulse period. In one example, transmitter 300 maybe configured to transmit via M segments, each segment having abandwidth of B MHz. In this case, analyzer 230-a may have M (or more)bandpass filters 332, each configured to pass a range of frequenciescorresponding to the bandwidth of one segment. That is, bandpass filters332 may be configured to pass frequencies in ranges of {0 to B}, {B to2B}, . . . {(M−1)*B to M*B}. Bandpass filters 332 may output filteredsegment waveforms 333.

Downconverters 234 may downconvert filtered segment waveforms 333 to abaseband frequency range. For example, downconverters 234 maydownconvert each filtered segment waveform 333 to have a frequency rangeof {0 to B}. Decimators 336 may decimate (e.g., downsample) thedownconverted filtered segment waveforms 333 from a first sample rateassociated with the first wideband waveform 220-a to a second, lowersample rate (e.g., which may not cause aliasing because of the smallerbandwidth of each segment). In some cases, bandpass filters 332 anddownconverters 334 may be implemented in a downconverting filter 330.Downconverting filter 330 may implement bandpass filters 332 using apolyphase filter and an inverse discrete Fourier transform (IDFT). Insome cases, both the inputs and the outputs of the inverse DFT are inthe time domain. It should be understood that the IDFT may beimplemented using an inverse fast Fourier transform (IFFT) algorithm,and the terms IDFT and IFFT may be used interchangeably.

Mapper 250-a may map the downconverted filtered segment waveforms 333 tosegments of a channel set (e.g., channel set 215-a). Mapper 250-a maymap downconverted filtered segment waveforms 333 to the segments inorder of the downconverted filtered segment waveforms 333.Alternatively, mapper 250-a may map the downconverted filtered segmentwaveforms 333 to the segments of the channel set using a scrambledmapping (e.g., not in order). Mapper 250-a outputs mapped segmentwaveforms 351, each mapped segment waveform 351 being a basebandwaveform sampled according to a baseband sampling frequency. Mapper250-a may output M mapped segment waveforms 351, where M corresponds toa number of segments in channel set 215-a (e.g., null segments may notcorrespond to a mapped segment waveform 351).

Synthesizer 255-a includes interpolators 352, image rejection (IR)filters 354, upconverters 356, and combiner 358. Interpolators 352effectively upsample the mapped segment waveforms 351 by interpolatingfrom the second sample rate to a third, higher sample rate (e.g., asample rate associated with a system bandwidth). For example,interpolators 352 may upsample the mapped segment waveforms 351 to asample rate that is based on an aggregate bandwidth of a total number ofchannels of the system bandwidth (e.g., a sample rate that satisfies theNyquist criteria for the system bandwidth).

Image rejection filters 354 may perform filtering to suppress imagespectra that may result from interpolation.

Upconverters 356 upconvert each mapped segment waveform 351 to afrequency of the channel set 215-a. For example, a first upconverter 356may upconvert a first mapped segment waveform 351 to a frequency of afirst channel of the channel set 215-a, a second upconverter 356 mayupconvert a second mapped segment waveform 351 to a frequency of asecond channel of the channel set 215-a, and so on, such that each ofthe mapped segment waveforms 351 are upconverted to respective channelsof the channel set 215-a. Combiner 358 combines the upconverted mappedsegment waveforms 351 to obtain second wideband waveform 270-a, whichmay include signal energy in channels of a system bandwidthcorresponding to channel set 215-a, and null waveforms (e.g., havingsubstantially no signal energy) in channels of the system bandwidth notwithin channel set 215-a. Upconverters 356 and combiner 358 may beimplemented as upconverting filter 350. In some cases upconvertingfilter 350 may implement upconverters 356 and combiner 358 using apolyphase filter and an inverse DFT.

FIG. 4 illustrates a spectrum plot 400 of a channelized widebandwaveform for transmission on a spectral band comprising unavailablechannel segments in accordance with aspects of the present disclosure.Spectrum plot 400 shows, for example, a system bandwidth 130-a thatincludes N channels 135-a. Each channel 135-a may have a channelbandwidth 410. Although FIG. 4 illustrates channels 135-a having thesame channel bandwidth 410, channels 135-a may have differentbandwidths, in some cases. In some examples, implementations using apolyphase synthesis bank or a polyphase analysis bank may be applied inenvironments where each channel 135 has the same channel bandwidth135-a, or are multiples of a power of two.

Spectrum plot 400 illustrates spectrum of a second wideband waveform270-b, which may be generated, for example, by the transmitters 200 or300 of FIG. 2 or 3 . Second wideband waveform 270-b may include signalpower within channels 135-a of a channel set, while channels that arenot included in the channel set may not have substantial signal power(e.g., may have null waveforms). For example, FIG. 4 illustrates thatsecond wideband waveform 270-b has signal power in channels 2, 4, 5, andN (with some channels not shown for the sake of clarity), while channels1, 3, and 6 have null signals (e.g., substantially no signal power). Thebandwidth of the signal power of second wideband waveform 270-b for eachchannel 135-a may be understood as the range of the spectral density ofthe channel 135-a that includes signal power over a threshold (e.g., 3dB, 6 dB). In some cases, the signal power waveform for each segment mayhave a guardband (e.g., a segment of 3 MHz may have guardbands of 100KHz, or a 3 dB bandwidth of 2.8 MHz).

FIGS. 5A and 5B illustrate examples of polyphase analysis bank 500 and apolyphase synthesis bank 505 that support channelizing a widebandwaveform for transmission on a spectral band comprising unavailablechannel segments in accordance with aspects of the present disclosure.In some examples, polyphase analysis bank 500 and polyphase synthesisbank 505 may implement aspects of wireless communication system 100.

Polyphase analysis bank 500 includes multiple polyphase filters. Forexample polyphase analysis bank 500 is illustrated with P subfilters 515and IDFT 525. Each subfilter 515 may have the same or different orders,and may be a bandpass filter. An input signal 520 (e.g., first widebandwaveform 220) may be input to subfilters 515 (e.g., different sampleinterlaces may be input to subfilters 515 by commutator 512) and theoutput of the subfilters 515 may be input to inverse DFT 525. Eachsubfilter 515 may receive an interlaced subset of samples of the inputsignal 520. For example, subfilters 515-a, 515-b, and 515-c may eachreceive different subsets of samples of the input signal 520. In somecases, commutator 512, subfilters 515, and IDFT 525 may implement adownconversion polyphase filter that outputs downconverted filteredwaveform segments 535. For example, commutator 512 may downsample theinput signal 520, subfilters 512 may perform filtering, and IDFT 525 mayperform downconversion. Polyphase analysis bank 500 may be an example ofa downconverting filter 330.

Polyphase synthesis bank 505 may also include multiple polyphasefilters. For example polyphase synthesis bank 505 is illustrated withIDFT 545 and Q subfilters 515. Each subfilter 515 (e.g., subfilters515-d, 515-e, 515-f and others) may have the same or different orders.Inverse DFT 545 may receive Q input signals (e.g., mapped segments 251)and output Q signals to subfilters 515. IDFT 545 and subfilters 515 mayperform filtering and upconversion to generate an upconverted waveformcombining the signal energy within the Q signals (e.g., corresponding toQ segments). For example, the output of subfilters 515 may be combinedby commutator 550 (e.g., by interlacing samples from the Q subfilters)to obtain the upconverted waveform (e.g., second wideband waveform 270).That is, IDFT 545 may perform upconversion, subfilters 515 may performimage reject filtering, and commutator 550 may perform upsampling.Polyphase synthesis bank 505 may be an example of an upconverting filter350.

FIG. 6 illustrates an example of a receiver 600 that supportschannelizing a wideband waveform for transmission on a spectral bandcomprising unavailable channel segments in accordance with aspects ofthe present disclosure. In some examples, receiver 600 may be includedin a wireless communication system, such as wireless communicationsystem 100.

Receiver 600 may be configured to wirelessly receive wideband waveformsover a tactical data link using one or more antennas 605. Receiver 600may be configured to receive a first wideband waveform 610 via a systembandwidth, which may be a band of frequencies over which receiver 600may receive signals. In some cases, a system bandwidth may bepartitioned into channels, with each channel having a respectivebandwidth (e.g., the same channel bandwidth).

In some cases, one or more channels of the system bandwidth of the firstwideband waveform 610 may be unused for a received signal (e.g., via a“net” of a tactical data link). Unused channels of the system bandwidthmay not include data to be received and/or may have a received level ofsignal power (e.g., signal energy) that is below a threshold. That is,in some cases, there may be substantial energy of the received signalonly in a subset of channels of the channels of the system bandwidth. Insome cases, the subset of channels may be non-contiguous; that is, atleast two channels in the subset of channels may be separated by one ormore channels that are excluded from the subset of channels. In somecases, receiver 600 identifies that a level of signal power for at leastone of the channels of the system bandwidth satisfies a threshold (e.g.,is below a minimum), and excludes such channel(s) from the subset ofchannels 615. Receiver 600 may identify or receive an indication of thesubset of channels of the system bandwidth associated with a signal forreception (e.g., channel set 615).

In some cases, receiver 600 may include a receiver frontend 607 thatincludes hardware or software to process a signal received usingantenna(s) 605 to generate first wideband waveform 610. For example,receiver frontend 607 may filter the received signal, mix the signal(e.g., downconvert), perform analog-to-digital conversion, and/orperform other processing.

Receiver 600 includes analyzer 620. Analyzer 620 includes segmenter 625for separating the first wideband waveform 610 into multiple segments635. Segments 635 may have respective bandwidths corresponding tochannel bandwidths of the channels of the system bandwidth (e.g., thesame bandwidth). In some cases, segmenter 625 may separate the firstwideband waveform 610 into segments 635 by applying multiple filters(such as BPFs) to the first wideband waveform 610. In some cases,segmenter 625 may include a series of filters to separate first widebandwaveform 610 into segments 635, and may be implemented using adownconverting filter. For example, analyzer 620 may be structurallysimilar to analyzer 230-a, downconverting filter 330, or polyphaseanalysis bank 500. In one example, analyzer 620 may be structurallysimilar to analyzer 230-a with M (or more) bandpass filters 332, where Mis the number of channels in channel set 615. Alternatively, analyzer620 may include N (or more) bandpass filters 332, where N is the totalnumber of channels of the system bandwidth.

In some cases, analyzer 620 includes downconverter 630 to downconvertthe segments 635 to baseband segments 645. For example, segments 635 mayeach be associated with different frequency ranges and downconverter 640may downconvert each segment 635 to a baseband frequency range.

Receiver 600 includes mapper 650 for de-mapping the segments (e.g.,baseband segments 645) corresponding to the channel set 615 to thecorresponding frequency ranges of synthesizer channels 690. In somecases, the remaining channels (e.g., channels of the system bandwidththat are not included in channel set 615) may be ignored. For example,the system bandwidth may include N channels while channel set 615 mayinclude M channels. Mapper 650 may map M channels of the N channels thatare in channel set 615 to a first set of M synthesizer channels 690while N-M channels of synthesizer channels 690 may not be mapped (e.g.,may have a null signal mapped). In some cases, de-mapping the segmentsmay include de-scrambling an order of the segments according to ascrambling sequence. The scrambling sequence may include an indicationof a scrambled order of the segments. In some cases, the scramblingsequence includes multiple sub-groups of the waveform segments, and thesub-groups are de-mapped from respective contiguous blocks of the subsetof the plurality of channels.

In some examples, mapper 650 may perform additional processing. Forexample, mapper 650 may perform multipath equalization of basebandsegments 645 before de-mapping the baseband segments 645.

Receiver 600 includes synthesizer 660 for generating a second widebandwaveform 675. Second wideband waveform 675 may have a bandwidth that isnarrower than first wideband waveform 610. Synthesizer 660 includesupconverter 665 for upconverting the de-mapped segments 655 to higherfrequencies. Synthesizer 660 includes combiner 670 for combining theupconverted de-mapped segments to obtain a second wideband waveform 675having a bandwidth corresponding to the total (e.g., aggregate)bandwidth of channel set 615. In some examples, synthesizer 660 may bestructurally similar to synthesizer 255-a, upconverting filter 350, orpolyphase synthesis bank 505. In one example, synthesizer 660 may bestructurally similar to synthesizer 255-a with M (or more) interpolators352, image rejection filters 354, and upconverters 356, where M is thenumber of channels in the channel set 615.

In some cases, receiver 600 may include hardware or software toimplement additional processing on second wideband waveform 675 togenerate a stream of bits 680 representing second wideband waveform 675.For example, receiver 600 may include a demodulator 685 to demodulatesecond wideband waveform 675 to obtain the stream of bits 680. In somecases, a receiver 600 may identify a modulation scheme (e.g., from a setof modulation schemes) for demodulating the second wideband waveform 675to obtain stream of bits 680 based on information associated with thesignal (e.g., from the transmitter). Receiver 600 may demodulate thesecond wideband waveform according to the selected modulation scheme.

Receiver 600 may provide the stream of bits 680 to a processor or otherdevice that is coupled with receiver 600.

In one example, a system bandwidth of 45 MHz may be configured with 3MHz channels (e.g., 15 channels). Receiver 600 may identify a channelset 615 for a first time period (e.g., a first pulse period) thatincludes channels 1-5, 8-10, 13, and 15 (e.g., including 10 of the 15channels). Receiver 600 may receive a first wideband waveform 610 (e.g.,via antenna(s) 605 and receiver frontend 607). The first widebandwaveform 610 may have a bandwidth corresponding to the system bandwidth(e.g., 45 MHz) with substantially no signal energy (e.g., associatedwith the signal to be received) in channels 6, 7, 11, 12, and 14.Analyzer 620 may segment and downconvert each segment to generate 15baseband segments 645, each representing a portion (e.g., 3 MHz) of the45 MHz bandwidth, and each having a baseband frequency range of 0-3 MHz.Mapper 650 may map the baseband segments 645 corresponding to channelset 615 to (e.g., a first 10) synthesizer channels 690, and may map nullwaveforms to other synthesizer channels 690 (e.g., synthesizer channels690 other than the first 10). Mapper 650 may map the baseband segments645 from analyzer 620 in order, or mapper 650 may map the basebandsegments 645 in a scrambled order. For example, mapper 650 may mapbaseband segments 1-5 to synthesizer channels 5-9, baseband segments8-10 to synthesizer channels 2-4, baseband segment 13 to synthesizerchannel 1, and baseband segment 15 to synthesizer channel 10.Synthesizer 660 may upconvert the mapped segments to frequenciescorresponding to a width of channels of the system bandwidth and combinethe upconverted segments to obtain a second wideband waveform 675. Inthis example, second wideband waveform 675 may have a bandwidth of 30MHz.

Receiver 600 may identify a new channel set 615 for a second time period(e.g., a second pulse period), and may perform the segmenting,downconverting, mapping, upconverting, and combining to generate asecond wideband waveform 675 for the second time period. New channel set615 may be different than the channel set 615 for the first pulse periodand may or may not have any channels in common with the previous channelset 615. For example, new channel set 615 may have the same or adifferent number of channels. It should be understood that this exampleis provided for the sake of clarity, and other system bandwidths andchannel bandwidths are contemplated without deviating from the scope ofthe application. For example, the system bandwidth may be 240 MHz, andthe system may have 80 channels where each channel has a 3 MHz channelbandwidth. Channel set 615 may have up to 51 channels in each pulseperiod and thus first wideband waveform 610 may have a bandwidth of upto 240 MHz while second wideband waveform 675 may have a bandwidth of upto 153 MHz (e.g., the system bandwidth).

FIG. 7 shows a diagram of a system 700 including a device 705 thatsupports channelizing a wideband waveform for transmission on a spectralband comprising unavailable channel segments in accordance with aspectsof the present disclosure. The device 705 may include components forbi-directional communications of wideband waveforms including componentsfor transmitting and receiving communications, including a processor710, an I/O controller 715, a transceiver 720, an antenna 725, andmemory 730. These components may be in electronic communication via oneor more buses (e.g., bus 740).

The processor 710 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 710 may be configured to operate a memoryarray using a memory controller. In other cases, a memory controller maybe integrated into the processor 710. The processor 710 may beconfigured to execute computer-readable instructions stored in a memory(e.g., memory 730) to cause the device 705 to perform various functions(e.g., functions or tasks supporting channelizing a wideband waveformfor transmission on a spectral band comprising unavailable channelsegments).

The I/O controller 715 may manage input and output signals for thedevice 705. The I/O controller 715 may also manage peripherals notintegrated into the device 705. In some cases, the I/O controller 715may represent a physical connection or port to an external peripheral.In some cases, the I/O controller 715 may utilize an operating systemsuch as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, oranother known operating system. In other cases, the I/O controller 715may represent or interact with a modem, a keyboard, a mouse, atouchscreen, or a similar device. In some cases, the I/O controller 715may be implemented as part of a processor. In some cases, a user mayinteract with the device 705 via the I/O controller 715 or via hardwarecomponents controlled by the I/O controller 715.

The transceiver 720 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 720 may represent a wireless transceiver and may communicatebi-directionally with another wireless transceiver. The transceiver 720may also include a modem to modulate signals and provide the modulatedsignals to the antennas for transmission, and to demodulate signalsreceived from the antennas.

In some cases, the wireless device may include a single antenna 725.However, in some cases the device 705 may have more than one antenna725, which may be capable of concurrently transmitting or receivingmultiple wireless transmissions.

The memory 730 may include RAM and ROM. The memory 730 may storecomputer-readable, computer-executable code 735 including instructionsthat, when executed, cause the processor to perform various functionsdescribed herein. In some cases, the memory 730 may contain, among otherthings, a BIOS which may control basic hardware or software operationsuch as the interaction with peripheral components or devices.

The device 705 may include channel manager 750. Channel manager 750 mayidentify a subset (e.g., channel set 215 or 615) of channels of a systembandwidth available for a transmission in a time period. Each of thechannels may have a respective channel bandwidth (e.g., the same channelbandwidth, or different channel bandwidths). The subset of the channelsmay be non-contiguous. In some examples, the subset of the channels maycorrespond to all of a set of available channels (e.g., a configured setof available channels, which may be a subset of the total channels ofthe system bandwidth). Alternatively, the subset of the channels may bea subset of the available channels (e.g., a configured number ofchannels). In some cases the subset of channels may be determined byexcluding channels from the available channels or configured channelsthat have a level of signal power (e.g., interference) that satisfies(e.g., meets or exceeds) a threshold.

The code 735 may include instructions to implement aspects of thepresent disclosure, including instructions to support methods fortransmitting and/or receiving channelized wideband waveforms asdescribed herein. For example, the code 735 may include instructions forperforming (e.g., by the processor 710 and/or the transceiver 720) thefunctions of the modulator 210, the analyzer 230 or 620, the mapper 250or 650, the synthesizer 255 or 660, and/or the demodulator 685. The code735 may be stored in a non-transitory computer-readable medium such assystem memory or other type of memory. In some cases, the code 735 maynot be directly executable by the processor 710 but may cause a computer(e.g., when compiled and executed) to perform functions describedherein.

FIG. 8 shows a flowchart illustrating a method 800 that supportschannelizing a wideband waveform for transmission on a spectral bandcomprising unavailable channel segments in accordance with aspects ofthe present disclosure. The operations of method 800 may be implementedby a transmitter or a device or their components as described herein.For example, the operations of method 800 may be performed by atransmitter as described with reference to FIGS. 2 through 5 and/or adevice as described with reference to FIG. 7 . In some examples, aprocessor may execute a set of instructions to control the functionalelements of the default to perform the functions described below.Additionally or alternatively, a transmitter may perform aspects of thefunctions described below using special-purpose hardware, programmablelogic, or other means.

At 805, the transmitter may identify a subset of a set of channels of asystem bandwidth available for a transmission in a time period (e.g.,channel set 215), where the subset of the set of channels isnon-contiguous, and where each of the set of channels has a respectivechannel bandwidth. For example, each of the set of channels may have thesame bandwidth, or some channels of the set of channels may havedifferent bandwidths from other channels. The operations of 805 may beperformed according to the methods described herein. In some examples,aspects of the operations of 805 may be performed by a transmitter asdescribed with reference to FIGS. 2 through 5 .

At 810, the transmitter may generate a first wideband waveform having abandwidth determined according to a number of channels in the subset ofthe set of channels. The operations of 810 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 810 may be performed by a transmitter as described withreference to FIGS. 2 through 5 .

At 815, the transmitter may separate the first wideband waveform into aset of segments, each segment of the set of segments having a bandwidthcorresponding to the respective bandwidth of the channel of the set ofchannels. The operations of 815 may be performed according to themethods described herein. In some examples, aspects of the operations of815 may be performed by a transmitter as described with reference toFIGS. 2 through 5 .

At 820, the transmitter may map the set of segments to the subset of theset of channels of the system bandwidth. The operations of 820 may beperformed according to the methods described herein. In some examples,aspects of the operations of 820 may be performed by a transmitter asdescribed with reference to FIGS. 2 through 5 .

At 825, the transmitter may combine the mapped set of segments togenerate a second wideband waveform. The operations of 825 may beperformed according to the methods described herein. In some examples,aspects of the operations of 825 may be performed by a transmitter asdescribed with reference to FIGS. 2 through 5 .

At 830, the transmitter may transmit the second wideband waveform in thetime period. The operations of 830 may be performed according to themethods described herein. In some examples, aspects of the operations of830 may be performed by a transmitter as described with reference toFIGS. 2 through 5 .

FIG. 9 shows a flowchart illustrating a method 900 that supportschannelizing a wideband waveform for transmission on a spectral bandcomprising unavailable channel segments in accordance with aspects ofthe present disclosure. The operations of method 900 may be implementedby a receiver or a device or their components as described herein. Forexample, the operations of method 900 may be performed by a receiver asdescribed with reference to FIG. 6 and/or a device as described withreference to FIG. 7 . In some examples, a processor may execute a set ofinstructions to perform the functions described below. Additionally oralternatively, a receiver may perform aspects of the functions describedbelow using special-purpose hardware or programmable logic.

At 905, a receiver may identify a subset of a set of channels of asystem bandwidth available for a transmission in a time period, wherethe subset of the set of channels is non-contiguous, and where each ofthe set of channels has a same channel bandwidth. The operations of 905may be performed according to the methods described herein. In someexamples, aspects of the operations of 905 may be performed by areceiver or device as described with reference to FIGS. 6 and 7 .

At 910, the receiver may receive a first wideband waveform in the timeperiod. The operations of 910 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 910 maybe performed by a receiver or device as described with reference toFIGS. 6 and 7 .

At 915, the receiver may separate the first wideband waveform into a setof waveform segments corresponding to the subset of the set of channels.The operations of 915 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 915 maybe performed by a receiver or device as described with reference toFIGS. 6 and 7 .

At 920, the receiver may de-map the set of waveform segments based onthe subset of the set of channels. The operations of 920 may beperformed according to the methods described herein. In some examples,aspects of the operations of 920 may be performed by a receiver ordevice as described with reference to FIGS. 6 and 7 .

At 925, the receiver may combine the de-mapped set of waveform segmentsto obtain a second wideband waveform. The operations of 925 may beperformed according to the methods described herein. In some examples,aspects of the operations of 925 may be performed by a receiver ordevice as described with reference to FIGS. 6 and 7 .

At 930, the receiver may demodulate the second wideband waveform toobtain a stream of bits. The operations of 930 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 930 may be performed by a receiver or device asdescribed with reference to FIGS. 6 and 7 .

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a DSP, an ASIC, an FPGA, or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described herein. A general-purpose processor may be amicroprocessor, but in the alternative, the processor may be anyconventional processor, controller, microcontroller, or state machine. Aprocessor may also be implemented as a combination of computing devices(e.g., a combination of a DSP and a microprocessor, multiplemicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described herein can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations.

Computer-readable media includes both non-transitory computer storagemedia and communication media including any medium that facilitatestransfer of a computer program from one place to another. Anon-transitory storage medium may be any available medium that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, non-transitory computer-readable media mayinclude random-access memory (RAM), read-only memory (ROM), electricallyerasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROMor other optical disk storage, magnetic disk storage or other magneticstorage devices, or any other non-transitory medium that can be used tocarry or store desired program code means in the form of instructions ordata structures and that can be accessed by a general-purpose orspecial-purpose computer, or a general-purpose or special-purposeprocessor. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, include CD, laser disc, optical disc,digital versatile disc (DVD), floppy disk and Blu-ray disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Combinations of the above are also includedwithin the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items(e.g., a list of items prefaced by a phrase such as “at least one of” or“one or more of”) indicates an inclusive list such that, for example, alist of at least one of A, B, or C means A or B or C or AB or AC or BCor ABC (i.e., A and B and C). Also, as used herein, the phrase “basedon” shall not be construed as a reference to a closed set of conditions.For example, an exemplary step that is described as “based on conditionA” may be based on both a condition A and a condition B withoutdeparting from the scope of the present disclosure. In other words, asused herein, the phrase “based on” shall be construed in the same manneras the phrase “based at least in part on.”

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label, or othersubsequent reference label.

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details forthe purpose of providing an understanding of the described techniques.These techniques, however, may be practiced without these specificdetails. In some instances, well-known structures and devices are shownin block diagram form in order to avoid obscuring the concepts of thedescribed examples.

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be readily apparent to those skilled in the art, and the genericprinciples defined herein may be applied to other variations withoutdeparting from the scope of the disclosure. Thus, the disclosure is notlimited to the examples and designs described herein, but is to beaccorded the broadest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. A method of operation by a communication device,the method comprising: identifying a set of available frequency channelsamong a plurality of frequency channels of a tactical data link;modulating a stream of bits to be transmitted, to form a first widebandwaveform having a bandwidth corresponding to an aggregate bandwidth ofthe available frequency channels in the set, the first wideband waveformbeing un-channelized with respect to the tactical data link; separatingthe first wideband waveform into as many bandwidth segments as there areavailable frequency channels in the set; mapping, as mapped signalsegments, the bandwidth segments to respective ones of the availablefrequency channels in the set and mapping, as mapped null segments, nullvalues to any unavailable frequency channels spanned by the set ofavailable frequency channels; and upconverting the mapped signalsegments and mapped null segments to the respective channel frequencies,to form a second wideband waveform that is channelized for transmissionover the tactical data link.
 2. The method of claim 1, furthercomprising transmitting the second wideband waveform.
 3. The method ofclaim 1, further comprising repeating the method for recurringtransmission times, such that the set of available frequency channelsidentified by the communication device in each transmission timereflects availability for each of the recurring transmission times. 4.The method of claim 3, wherein the recurring transmission times are timeintervals defined by a time division multiple access (TDMA) scheme ofthe tactical data link.
 5. The method of claim 1, wherein the mappingstep includes mapping null values to all frequency channels of thetactical data link that do not belong to the set of available frequencychannels.
 6. The method of claim 1, wherein separating the firstwideband waveform into as many bandwidth segments as there are availablefrequency channels in the set comprises using a polyphase filter toobtain the bandwidth segments.
 7. The method of claim 1, furthercomprising downconverting the bandwidth segments to baseband beforecarrying out the mapping step.
 8. The method of claim 1, wherein mappingthe bandwidth segments to respective ones of the available frequencychannels in the set comprises mapping the bandwidth segments in segmentorder.
 9. The method of claim 1, wherein mapping the bandwidth segmentsto respective ones of the available frequency channels in the setcomprises mapping the bandwidth segments out of segment order.
 10. Themethod of claim 1, wherein modulating the stream of bits comprisesmodulating the stream of bits based on the number of available frequencychannels in the set, such that the energy of each bit is spread across asignal bandwidth equal to an aggregate bandwidth of the availablefrequency channels in the set.
 11. The method of claim 1, whereinidentifying the set of available frequency channels comprises excludingany frequency channels of the tactical data link that are known ordetected as being unavailable.
 12. A communication device comprising:control circuitry configured to identify a set of available frequencychannels among a plurality of frequency channels of a tactical datalink; and a transmitter comprising: modulator circuitry configured tomodulate a stream of bits to be transmitted, to form a first widebandwaveform having a bandwidth corresponding to an aggregate bandwidth ofthe available frequency channels in the set, the first wideband waveformbeing un-channelized with respect to the tactical data link; analyzercircuitry configured to separate the first wideband waveform into asmany bandwidth segments as there are available frequency channels in theset; mapping circuitry configured to map, as mapped signal segments, thebandwidth segments to respective ones of the available frequencychannels in the set and map, as mapped null segments, null values to anyunavailable frequency channels spanned by the set of available frequencychannels; and synthesizer circuitry configured to upconvert the mappedsignal segments and mapped null segments to the respective channelfrequencies, to form a second wideband waveform that is channelized fortransmission over the tactical data link.
 13. The communication deviceof claim 12, further comprising transmitter backend circuitry configuredto transmit the second wideband waveform.
 14. The communication deviceof claim 12, wherein the control circuitry is configured to identify theset of available frequency channels for respective ones among recurringtransmission times, such that the set of available frequency channelsused by the communication device in each transmission time reflectsavailability as determined by the communication device for eachtransmission time.
 15. The communication device of claim 14, wherein therecurring transmission times are time intervals defined by a timedivision multiple access (TDMA) scheme of the tactical data link. 16.The communication device of claim 12, wherein the mapping circuitry isconfigured to map null values to all frequency channels of the tacticaldata link that do not belong to the set of available frequency channels.17. The communication device of claim 12, wherein the analyzer circuitrycomprises a polyphase filter.
 18. The communication device of claim 12,wherein the analyzer circuitry comprises downconversion circuitry thatis configured to downconvert the bandwidth segments to baseband, formapping by the mapping circuitry.
 19. The communication device of claim12, wherein the mapping circuitry is configured to map the bandwidthsegments in segment order.
 20. The communication device of claim 12,wherein the mapping circuitry is configured to map the bandwidthsegments out of segment order.
 21. The communication device of claim 12,wherein the modulator circuitry is configured to modulate the stream ofbits based on the number of available frequency channels in the set,such that the energy of each bit is spread across a signal bandwidthequal to an aggregate bandwidth of the available frequency channels inthe set.
 22. The communication device of claim 12, wherein, to identifythe set of available frequency channels, the control circuitry isconfigured to exclude any frequency channels of the tactical data linkthat are known or detected as being unavailable.
 23. A method ofoperation by a communication device, the method comprising: receiving afirst wideband waveform over a tactical data link comprising a pluralityof frequency channels, the first wideband waveform conveying a stream ofbits and channelized for the tactical data link by having signal energyon particular ones of the frequency channels and signal nulls onremaining ones of the frequency channels; separating the first widebandwaveform into bandwidth segments corresponding to the frequencychannels, the bandwidth segments corresponding to the particular ones ofthe frequency channels being signal segments; de-mapping the signalsegments from the frequency channels and combining them to form a secondwideband waveform that is un-channelized with respect to the tacticaldata link; and demodulating the second wideband waveform to recover astream of bits.
 24. The method of claim 23, wherein de-mapping thesignal segments includes descrambling an order of the signal segments,so that the signal segments after de-mapping are in a defined segmentorder associated with channelizing operations at a transmitter thatoriginated the first wideband waveform.
 25. The method of claim 23,wherein de-mapping the signal segments includes downconverting them tobaseband, for combining.
 26. The method of claim 23, wherein combiningthe signal segments to form the second wideband waveform comprisescombining the signal segments after upconverting each signal segment toa respective frequency.
 27. A communication device comprising areceiver, wherein the receiver comprises: front-end reception circuitryconfigured to receive a first wideband waveform over a tactical datalink comprising a plurality of frequency channels, the first widebandwaveform conveying a stream of bits and channelized for the tacticaldata link by having signal energy on particular ones of the frequencychannels and signal nulls on remaining ones of the frequency channels;analyzer circuitry configured to separate the first wideband waveforminto bandwidth segments corresponding to the frequency channels, thebandwidth segments corresponding to the particular ones of the frequencychannels being signal segments; de-mapping circuitry configured tode-map the signal segments from the frequency channels; synthesizercircuitry configured to combine the signal segments after de-mapping, toform a second wideband waveform that is un-channelized with respect tothe tactical data link; and demodulator circuitry configured todemodulate the second wideband waveform to recover a stream of bits. 28.The communication device of claim 27, wherein the de-mapping circuitryis configured to descramble an order of the signal segments, so that thesignal segments after de-mapping are in a defined segment orderassociated with channelizing operations at a transmitter that originatedthe first wideband waveform.
 29. The communication device of claim 27,wherein the de-mapping circuitry is configured to downconvert the signalsegments to baseband.
 30. The communication device of claim 27, whereinthe synthesizer circuitry is configured to combine the signal segmentsto form the second wideband waveform after upconverting each signalsegment to a respective frequency.